CLIMBING AND WATER PLANTS 125 



that it is only an apparent, and not a real 

 risk. The fact is, the veins form a beautiful 

 system of unions or anastomoses, and these 

 are often arranged in a series of arches which 

 pass just under the indentations characteristic 

 of the leaf margins of so many plants. 



There are certain exceptions, however, to 

 the general rule that leaf construction is 

 adapted to prevent tearing. All palms have 

 leaves which are primarily undivided. But 

 by complicated processes which result in the 

 dying out of strips of leaf tissue extending 

 from the midrib to the margin, the leaf 

 surface as a whole may be broken up into 

 strips resembling pinnae or leaflets. This 

 occurs in the Coco-nut, and many other 

 palms. These " leaflets " are very different 

 from the true leaflets of a vetch and most 

 other plants, where they arise as the result 

 of a true process of branching. The so-called 

 fan-leaved palms have leaves in which there 

 is no great elongation of the " midrib," and 

 the pleated or concertina-like folding represent 

 the imperfect separation of the " leaflet " 

 which is only completely carried out in forms 

 like the Coco-nut, Areca, and other pinnate- 

 leaved species. 



The Banana plant is especially interesting 

 in this connection, for it is provided by 

 nature with a leaf quite unsuitable for a 

 plant growing in any but the most sheltered 

 situations. The banana plant consists of a 

 thick herbaceous axis, sheathed by the bases 



